F- WL/VARA HF at 10W OK but FT8 only 2W

I can run Winlink/VARA FH on 40m at full power (10W, QRP rig - IC 703). But not FT8. I have beads on everything - antenna, usb cable, even an armored usb cable. The most power that works consistently with FT8 is 2W. OK so it’s RFI. How many more beads do I need.??? thanks for your consideration. Jim/K2JJK

That’s frustrating. Can you move the antenna farther from the transmitter?

73 Constrainted

Thanks for replying.
Well the antenna itself is in the attic so it is at least 20 feet away.
Although, right over the shack where the radio is. So, sounds like
the problem. Appreciate the insight. Tomorrow I’ll hook it up to an
outside antenna. Why didn’t I think of this.
best, jim

20 ft is already pretty far away. Let us know if there is any improvement with a more distant antenna. Another concern I have is the quality of my ferrite beads. I seem to do well with ferrites from Mouser, but who knows?

73 Constrainted

Once again thank you.
Yes, I too wonder about the beads. Good news is next week is the Melbourne FL hamfest.
Looking for some large ones.
best, jim

Well, external antenna made things worse.
I’m running 10W into an EFHW resonant on 20m and 40m
Winlink/VARA HF works on both bands.
FT8 now will not work on 20m (did before with the attic antenna)
and 40m (did not before.
Thoughts, please. Appreciate all the help I can get or this has to go
back and I’ll use my Signalink.

What are the symptoms? Are you getting the error messages on TX?
Can you share the screenshot?

Sure and many thanks.
The issue the software susceptible to rf. FT8, etc. uses hamlib which is
getting all the errors.
No time now but back soon. Again, the support is wonderful. best, jim/K2JJK

From Jim/K2JJK re: unresolved rf problem with ft8 at 10W
Rig = IC 703, Antenna = outside EFHW (resonant), armored USB cable
with ferrite beads at both ends.
Hope this helps.
best and thanks, jim


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This looks like some disruption in the serial communication. You can always fall back to Signalink’s level of features by not using CAT control and you’ll still have better PTT mechanism.

Still, it would be great to have it all working. Have you ever got CAT control working reliably using a separate USB dongle? We could use the settings from that knowing that they work. Alternatively we can try different stop bits, adding middleware CAT control software capable of retries on failures etc.


Thanks for the continued efforts.
No problem “falling back to Signalink level of operation”, but having trouble getting anything working.
Unplugged the green-serial cord. Now no TX.
Reconnected the “green” cord back in and unplugged the cord labelled audio and
now no audio, as expected So?
Thoughts? jk

Please make sure PTT set to RTS. That should give you TX with serial cable (green) disconnected.

Let me respond quickly here and I’ll post on the forum later.
But, it’s working!!!1
Appreciate all the help and kindness and persistence in helping me.
The net is I disabled CAT control in WSJT (FT8). Operating without
CAT is not a problem. CAT does work with Winlink and VarAC where
the latter will frequency hop. The problem is not a Digirig problem. It
is a hamlib issue operating with the IC 703. Again, thanks for the help.
best, jim